Ionic Compounds and Metals
Section 7.1 Ion Formation
Section 7.2 Ionic Bonds and Ionic
Compounds
Section 7.3 Names and Formulas
for Ionic Compounds
Section 7.4 Metallic Bonds and the
Properties of Metals
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Section 7.1 Ion Formation
• Define a chemical bond.
• Describe the formation of
positive and negative ions.
• Relate ion formation to
electron configuration.
octet rule: atoms tend to
gain, lose, or share
electrons in order to acquire
eight valence electrons
chemical bond
cation
anion
Ions are formed when atoms gain or
lose valence electrons to achieve a
stable octet electron configuration.
Valence Electrons and Chemical Bonds
• A ____________ ________ is the force
that holds two atoms together.
• Chemical bonds form by the attraction
between the positive nucleus of one atom
and the negative electrons of another atom.
Valence Electrons and Chemical Bonds (cont.)
• Atom’s try to form the octet—the stable
arrangement of eight valence electrons in
the outer energy level—by gaining or losing
valence electrons.
Positive Ion (Cation) Formation
• A positively charged ion is called a ________.
Positive Ion Formation (cont.)
• Metals are reactive because they lose
valence electrons easily.
Positive Ion Formation (cont.)
• Transition metals commonly form +2 or +3
ions, but can form greater than +3 ions.
• Other relatively stable electron arrangements
are referred to as pseudo-noble gas
configurations.
Negative Ion (Anion) Formation
• An ____________ is a negatively charged ion.
• Most nonmetal ions gain the number of
electrons required to fill an octet.
Section 7.2 Ionic Bonds and Ionic Compounds
• Describe the formation of ionic bonds and the
structure of ionic compounds.
• Generalize about the strength of ionic bonds based
on the physical properties of ionic compounds.
• Categorize ionic bond formation as exothermic or
endothermic.
compound: a chemical combination of two or more
different elements
Section 7.2 Ionic Bonds and Ionic Compounds
(cont.)
ionic bond
ionic compound
crystal lattice
electrolyte
lattice energy
Oppositely charged ions attract each
other, forming electrically neutral ionic
compounds.
Formation of an Ionic Bond
• The electrostatic force that holds oppositely
charged particles together in an ionic
compound is called an ionic bond.
• Compounds that contain ionic bonds are
called ionic compounds.
• Binary ionic compounds contain only two
different elements—a metallic cation and a
nonmetallic anion.
• The repeating pattern of particle packing in an
ionic compound is called an ionic crystal.
Properties of Ionic Compounds
(cont.)
• The strong attractions among the positive
and negative ions result in the formation of
the crystal lattice.
• A crystal lattice is the three-dimensional
geometric arrangement of particles, and is
responsible for the structure of many
minerals.
Properties of Ionic Compounds
(cont.)
• Melting point, boiling point, and hardness
depend on the strength of the attraction.
Properties of Ionic Compounds
(cont.)
• This figure demonstrates how and why
crystals break when an external force is
applied.
Properties of Ionic Compounds
(cont.)
• In a solid, ions are locked into position and
electrons cannot flow freely—solid ions are
poor conductors of electricity.
• Liquid ions or ions in aqueous solution have
electrons that are free to move, so they
conduct electricity easily.
• An ion in aqueous solution that conducts
electricity is an electrolyte.
Section 7.3 Names and Formulas for
Ionic Compounds
• Relate a formula unit of an ionic compound to its
composition.
• Write formulas for ionic compounds and oxyanions.
• Apply naming conventions to ionic compounds and
oxyanions.
nonmetal: an element that is generally a gas or a
dull, brittle solid and is a poor conductor of heat and
electricity
Section 7.3 Names and Formulas for
Ionic Compounds (cont.)
formula unit
monatomic ion
oxidation number
polyatomic ion
oxyanion
In written names and formulas for ionic
compounds, the cation appears first,
followed by the anion.
Formulas for Ionic Compounds
• Chemists around the world need to
communicate with one another, so a
standardized system of naming compounds
was developed.
• A formula unit or _________ ________
represents the simplest ratio of the ions
involved.
Formulas for Ionic Compounds
(cont.)
• The symbol for the cation (+) is always written first,
followed by the symbol of the anion (-).
• Subscripts represent the number of ions of each
element in an ionic compound.
• The total charge must equal zero in an ionic
compound.
CaO
NaP
AlS
Formulas for Ionic Compounds
(cont.)
• Polyatomic ions are ions made
up of more than one atom.
• Never change subscripts of
polyatomic ions,
• place in parentheses and write
the appropriate subscript
outside the parentheses.
• Ca (NO3) 2
Names for Ions and Ionic Compounds
(cont.)
• Chemical nomenclature is a systematic
way of naming compounds.
– Name the cation followed by the anion.
– For monatomic, cations use the element name.
– For monatomic anions, use the root element name
and the suffix –ide.
– To distinguish between different charges of the
same element, the Roman Numeral representing
the oxidation state is written in parentheses after
the name of the cation.
– When the compound contains a polyatomic ion,
name the cation followed by the name of the
polyatomic ion.
Names for Ions and Ionic Compounds
(cont.)
Section 7.4 Metallic Bonds and the
Properties of Metals
• Describe a metallic bond.
• Relate the electron sea model to the physical
properties of metals.
• Define alloys, and categorize them into two basic
types.
physical property: a characteristic of matter that
can be observed or measured without altering the
sample’s composition
Section 7.4 Metallic Bonds and the
Properties of Metals (cont.)
electron sea model
delocalized electron
metallic bond
alloy
Metals form crystal lattices and can be
modeled as cations surrounded by a
“sea” of freely moving valence
electrons.
Metallic Bonds and the Properties of Metals
• Metals are not ionic but share several
properties with ionic compounds.
• Metals also form lattices in the solid state,
where 8 to 12 other atoms closely surround
each metal atom.
Metallic Bonds and the Properties of Metals
(cont.)
• Within the crowded lattice, the outer energy
levels of metal atoms overlap.
• The electron sea model proposes that all
metal atoms in a metallic solid contribute their
valence electrons to form a "sea" of electrons.
• The electrons are free to move around and
are referred to as delocalized electrons,
forming a metallic cation.
Metallic Bonds and the Properties of Metals
(cont.)
• A metallic bond is the attraction of an
metallic cation for delocalized electrons.
Metallic Bonds and the Properties of Metals
(cont.)
• Boiling points are
much more extreme
than melting points
because of the
energy required to
separate atoms from
the groups of cations
and electrons.
Metallic Bonds and the Properties of Metals
(cont.)
• Metals are malleable because they can be
hammered into sheets.
• Metals are ductile because they can be
drawn into wires.
Metallic Bonds and the Properties of Metals
(cont.)
• Mobile electrons around cations make
metals good conductors of electricity and
heat.
• As the number of delocalized electrons
increases, so does hardness and strength.
Metal Alloys
• An alloy is a mixture of elements that has
metallic properties.
• The properties of alloys differ from the
elements they contain.
Metal Alloys (cont.)